connection issues with MS tools



I've tried to install your webpart on one of our sharepoints.
For this purpose I've tried to upload it directly in the same window, when adding an existing webpart, when editing a page.
When the upload finished, I hadn't found the webpart on the sharepoint and then 1 minute later, my OneNote, SharePoint Designer & Infpath, weren't able to connect to the sharepoint anymore.

I also can't see a feature or solution on the sharepoint with the name "spactivityfeed".

These are the errors:

OneNote must be online to complete this operation

SharePoint Designer:

Unable to open Web site. Possible causes:
1. The Web server my not have SharePoint Server installed.
2. The Web server may be temporarily out of service.
3. If you are connecting through a proxy server, the proxy setting may be incorrect.
4. An error may have occured in the Web server


Unable to connect to the SharePoint site.
InfoPath either cannot connect to the data source, the service has timed out, or the server has an invalid certificate.
Do you know what could be the cause of this issue?

Many, many thanks